SSL/TLS Certificate Lookup
Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted
okazaki-city.jp
SSL/TLS Certificate
SSL/TLS Certificate for okazaki-city.jp
Hostname mismatch- Issued by (CA)
- Let's Encrypt
- Subject
- www3.sinfonia.or.jp
- Valid from
- Sep 21, 2026
- Valid until
- Dec 20, 2026 (46 days remaining)
- Public key
- RSA 4096-bit
- Serial
- 066F5285B370098CDF57FA825E678FA6A2B4
- SHA-256 fingerprint
- 88:D8:8A:5A:DC:05:AC:BD:98:E6:2E:49:6F:A1:D3:28:29:DD:56:2D:61:F1:46:0F:53:E6:D2:86:04:F2:DF:67
- Chain
- YR1 → Root YR → ISRG Root X1
Certificate Authority Authorization (CAA)
No CAA policy is published for this domain — any certificate authority may issue for it.
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Uptime
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DNS changes
We watch NS, MX, CAA, CNAME, TXT and A/AAAA records, and identify the host, network, and ASN behind them, so a real migration or hijack stands out from routine noise.
TLS certificate
We warn you 30, 14, 7, and 1 days before it expires, and flag it if the issuing authority changes or the certificate is unexpectedly replaced.
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